With millions of toys rendered defective by lead paint or other hazards now on global recall, questions about how to safely dispose of them remain two days after the latest recall.

Consumer watchdogs and environmental experts are worried about the potential environmental or health risks the discarded toys could pose, depending on how many are thrown out at once.

"The size of this recall is really unprecedented and it doesn't seem like a very good solution to throw everything into the landfill sites," said Anne Wordsworth, a research associate with the Canadian Environmental Law Association.

"There is a problem with the leachate from landfill sites being contaminated with lead and other metals because of those products, so it doesn't sound like a particularly good way to deal with those things."

Mattel Inc., which recalled 436,000 die-cast Sarge cars worldwide on Tuesday because they contain high levels of lead that pose a health threat to young children, said it is working on a "responsible approach" to the toys' disposal, but could not provide details. The toy giant also recalled more than 18 million magnetic toys over safety concerns.

This week's announcement came just two weeks after the company recalled about 1.5 million preschool toys because paint on them contained excessive amounts of the toxic metal.

Health Canada is urging parents to either return the toys to Mattel or dispose of them as part of their regular household waste, saying the disposal of a limited number of such items through normal waste would not have a significant environmental impact.

The federal health agency said that the health and environmental risks associated with lead-contaminated toys depends on "how much product is being disposed of, how readily the lead leaches out of the product, and on the containment provisions at the facility."

Mattel recalled about 32,800 lead-paint toys in Canada on Tuesday, while an initial 42,000 were recalled on Aug. 1. In June, around 90,000 Thomas & Friends wooden railway toys were recalled in Canada by RC2 Corp. because of lead contamination.

Mattel is telling parents to take the products away from children and contact the company to arrange their return. They are also offering replacement vouchers for a toy of the consumer's choice, up to the value of the returned product.

Unsure of numbers

Just how many parents will take the time to return their defective toys or simply trash them remains to be seen.

Some industry watchers believe parents may find returning a toy and waiting for a voucher a cumbersome process and opt instead to throw them out.

"Ultimately, this problem is also creating a landfill problem because most of these products are not likely to be captured by manufacturers," said Perry Gottesfeld, executive director of Occupational Knowledge International, a San Francisco-based non-profit group that tracks environmental health issues.

Some parents may also be reluctant to trade one Chinese-made toy for another. Mattel has said it will continue manufacturing toys there, despite the recent problems.

Leigh Poirier, executive director of the Canadian Toy Testing Council, said her organization has received lots of calls from concerned parents who now think anything made in China is "unworthy."

She also expressed concerns with sending the contaminated toys to a landfill, and said it is up to the company to communicate clearly how the products should be disposed of. 

With files from the Associated Press